Although painful GI problems are common in children with ASD, such children may be unable to adequately communicate their discomfort because of verbal barriers and problems with sensory localization, lead author Kara Gross Margolis, MD, associate professor of pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Columbia University Medical Center, New York City, told Medscape Medical News.

The new screen is "an effective first step" toward changing that, said Margolis, who specializes in GI conditions in this patient population.

"I think it's probably the most effective, efficient screen that's available as of yet," she said.

The study was published online October 22 in the Journal of Autism and Developmental Disorders.

Aiming for a Better Screen

A relatively long GI screening questionnaire was developed by the Autism Treatment Network (ATN), a group of medical centers working with Autism Speaks to study medical problems that accompany autism.

Researchers aimed to develop a shorter, more accurate version of the questionnaire. Margolis notes that medical professionals have limited time to see patients and that patients with ASD "can be extremely challenging behavior-wise" in the medical office.

"The original questionnaire had many questions, but we didn't know which ones were going to be most effective in picking up GI problems," said Margolis.

To find out, the researchers carried out a two-stage study at two sites.

In the first stage, parents completed the longer ATN questionnaire. Among other things, the questionnaire asks about the presence of various GI signs and symptoms, such as pain, nausea, and bloating over the past 3 months, the past year, or ever, depending on the condition.

For bowel movements, parents were asked about frequency and consistency.

In the second stage, pediatric gastroenterologists, who were unaware of parental responses to the questionnaire, evaluated each child for the presence or absence of functional constipation, functional diarrhea, and GERD.

The authors struggled with including the word "functional" but did so to indicate that there is "no true organic cause that can be identified," said Margolis. For example, functional diarrhea is not associated with an infection or with lactose intolerance.

She added that diagnosing a GI disorder on the basis of symptoms and history can be challenging in children with ASD.

Of the 131 children with ASD in the sample, 82.4% were male, 25.2% represented a minority, and 43.4% were nonverbal.

High Sensitivity

GI disorders were highly prevalent, with 58.0% of the total sample having received at least one diagnosis at the study consultation. The most common was functional constipation (35.1%), followed by GERD (29.8%) and functional diarrhea (5.3%).

Of all the patients who had at least one GI disorder, 32.9% had a "newly recognized" disorder, and 64.5% had a GI disorder that had been previously recognized.

Given the social communication and sensory processing impairments in children with ASD, it wasn't surprising that rates at which parents responded, "unsure," were higher for the few items that assessed symptoms (subjective experiences of GI disorders) than for signs (observable manifestations of GI disorders) and did not differ by age or spoken language level, note the authors.

Using data from both stages, the study identified 17 maximally predictive items as a screen for the three common GI disorders in children with ASD.

The item "choke, gag, cough, or sound wet during or after swallowing or with meals" identified 40.5% of patients with GERD with high specificity (89.7%).

Other motor acts, such as the child's tilting his or her head to the side and arching their back, pushing the abdomen with his or her hands, and pushing his or her abdomen against furniture, were helpful in increasing the sensitivity of the screen for GERD.

The combination of the three screens had a sensitivity of 83.6%.

Diagnosis Challenging

Although the screen was "quite good" at identifying children with diarrhea, constipation, or GERD, the 43.4% specificity "was not great," said Margolis.

"A lot of that is the fact that many of these children are not verbal, and even if they have good verbal ability, their sensory vocalization is quite poor. So being able to actually say what their symptoms are, or even if they can say that they're having some sort of discomfort, being able to tell you where it is is very challenging."

The positive predictive value was 67.0%. A third of the children in the sample whose screens were positive did not ultimately have one of the three GI disorders; Margolis said that this was not unexpected in children who are unable to tell you what the problem is.

"We know that GI conditions are at least fourfold more common in kids with ASD. If we can say there was over 80% sensitive in accurately picking that up, we are willing to take a high false positive rate to make sure we don't miss those kids. The alternative is just referring every single child."

Margolis believes a combination of factors contributes to the relatively high rate of GI disorders in children with ASD. One factor could be that they are taking antipsychotic medication, a "prominent" side effect of which is constipation.

Also, in children with ASD, brain-gut communication is often impaired.

"The act of stooling, and the feeling you have to stool, takes a communication between the brain and gut," said Margolis. "If that sensation, or brain-gut communication, is impacted, you may not even feel you have to go to bathroom."

In addition, common signaling pathways may affect both brain formation and gut nervous system formation, she said.

A New Roadmap

Margolis views the shortened screen being used as a "road map" for parents of children with ASD as well as psychiatrists, neurologists, and primary care physicians who regularly treat these children.

"It's important to consider GI problems in a child with ASD who is exhibiting challenging or difficult behaviors," she said.

If the screen is positive, these patients should be referred to a gastroenterologist, she said.

The brief screen is now ready for a validation study in an independent clinical sample of children with ASD.

"We will be looking at various factors to figure out specifically which behaviors have the highest sensitivity in picking up GI conditions," said Margolis.

If it is validated, the short screen could reduce the time and cost of recruiting children with ASD who need to be diagnosed with GI disorders before inclusion in a clinical trial.

A limitation of the study is its relatively small number of patients with functional diarrhea. Further research with different and larger samples will determine whether the low prevalence of functional diarrhea was unique to the study's sample, the authors note.

Helpful Tool

Commenting for Medscape Medical News, David Beversdorf, MD, Thompson Center for Autism and Neurodevelopmental Disorders, University of Missouri, Columbia, said the study describes a "helpful tool."

In assessing GI problems in the ASD population, consideration needs to be given to the fact that not all patients with ASD are verbal, said Beversdorf.

"This study focuses on parent report to address this issue," he said.

Beversdorf noted other positive features of the study. For example, it "maximized objectivity" by focusing on "observable manifestations" and "subtle motor acts" induced by GI problems, he said.

The analysis covered constipation and diarrhea, as well as GERD, "for a broad spectrum of the GI issues with which ASD patients suffer," he added.

Moreover, it did so with a smaller set of maximally predictive items, for a briefer assessment.

"The combination of these features seems to suggest that it will be quite useful in the clinical as well as the research setting, after further validation testing."

The study was funded by the Massachusetts General Hospital and the Columba University Medical Center. Dr Margolis has disclosed no relevant financial relationships. Dr Beversdorf reported that the first author of the study is a good friend of his and that another author is a former mentor of his.

Authors and Disclosures

Authors and Disclosures

Journalist

Pauline Anderson

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